Final Presentation

Description

Presentations of the projects are given a few days after the Final Demo to an audience of fellow student reviewers, the lab instructors, and occasionally faculty or even students from outside the class who are following up a project of personal interest to them. The style is formal and professional, and students should dress accordingly (Generally business professional, or what you would wear to a career fair).

Requirements and Grading

Each project team has 25 minutes for a Powerpoint presentation and questions. Every group member must present their own work contributing to the project and be ready to answer questions. Presentations are judged on the basis of presentation technique and of technical organization and content.

Presentation technique includes dress, use of display materials (slides), clarity of speech, absence of filler words/fidgeting, proper eye contact with audience and smooth transitions between speakers. Content is judged on use of a proper introduction, orderly and connected development of ideas, absence of unnecessary details, proper pacing to stay within the allotted time, and an adequate summary at the close of the talk. Quantitative results are expected whenever applicable. Here is a general outline to follow:

  1. Introduction to your team and your project.
  2. Objective. What problem are you solving?
  3. Brief review of original design, statement on areas of design that changed, and overview of each functional block's requirements.
  4. Description of project build and functional test results. You can choose to include a short (30s) video of your project here.
  5. Discussion of successes and challenges, as well as explanations of any failed verifications demonstrating and understanding of the engineering reason behind the failure
  6. Conclusions from the project: what did you learn, what would you do differently if you redesigned your project, etc.
  7. Recommendations for further work.

Any significant, relevant ethical issues should be briefly addressed, preferably in a single slide.

Presentations will be graded using the presentation grading rubric. Your slides should follow ECE or College of Engineering presentation theming.

Submission and Deadlines

Slides for your final presentation must be uploaded to your project page on PACE prior to your presentation time. Deadlines for signing up may be found on the Calendar. Sign-up for the final presentation is done through PACE. Remember to sign up for a peer review of another group.

Instant Nitro Cold Brew Machine

Danis Heto, Mihir Vardhan

Instant Nitro Cold Brew Machine

Featured Project

# Instant Nitro Cold Brew Machine

Team Members:

- Mihir Vardhan (mihirv2)

- Danis Heto (dheto3)

# Problem

Cold brew is made by steeping coffee grounds in cold water for 12-18 hours. This low-temperature steeping extracts fewer bitter compounds than traditional hot brewing, leading to a more balanced and sweeter flavor. While cold brew can be prepared in big batches ahead of time and stored for consumption throughout the week, this would make it impossible for someone to choose the specific coffee beans they desire for that very morning. The proposed machine will be able to brew coffee in cold water in minutes by leveraging air pressure. The machine will also bring the fine-tuning and control of brewing parameters currently seen in hot brewing to cold brewing.

# Solution

The brew will take place in an airtight aluminum chamber with a removable lid. The user can drop a tea-bag like pouch of coffee grounds into the chamber along with cold water. By pulling a vacuum in this chamber, the boiling point of water will reach room temperature and allow the coffee extraction to happen at the same rate as hot brewing, but at room temperature. Next, instead of bringing the chamber pressure back to atmospheric with ambient air, nitrogen can be introduced from an attached tank, allowing the gas to dissolve in the coffee rapidly. The introduction of nitrogen will prevent the coffee from oxidizing, and allow it to remain fresh indefinitely. When the user is ready to dispense, the nitrogen pressure will be raised to 30 PSI and the instant nitro cold brew can now be poured from a spout at the bottom of the chamber.

The coffee bag prevents the coffee grounds from making it into the drink and allows the user to remove and replace it with a bag full of different grounds for the next round of brewing, just like a Keurig for hot coffee.

To keep this project feasible and achievable in one semester, the nitrogenation process is a reach goal that we will only implement if time allows. Since the vacuum and nitrogenation phases are independent, they can both take place through the same port in the brewing chamber. The only hardware change would be an extra solenoid control MOSFET on the PCB.

We have spoken to Gregg in the machine shop and he believes this vacuum chamber design is feasible.

# Solution Components

## Brewing Chamber

A roughly 160mm tall and 170mm wide aluminum chamber with 7mm thick walls. This chamber will contain the brew water and coffee grounds and will reach the user-set vacuum level and nitrogenation pressure if time allows. There will be a manually operated ball valve spout at the bottom of this chamber to dispense the cold brew once it is ready. The fittings for the vacuum hose and pressure sensor will be attached to the screw top lid of this chamber, allowing the chamber to be removed to add the water and coffee grounds. This also allows the chamber to be cleaned thoroughly.

## Temperature and Pressure Sensors

A pressure sensor will be threaded into the lid of the brewing chamber. Monitoring the readings from this pressure sensor will allow us to turn off the vacuum pump once the chamber reaches the user-set vacuum level. A temperature thermocouple will be attached to the side of the brewing chamber. The temperature measured will be displayed on the LCD display. This thermocouple will be attached using removable JST connectors so that the chamber can be removed entirely from the machine for cleaning.

## Vacuum Pump and Solenoid Valve

An oilless vacuum pump will be used to pull the vacuum in the brewing chamber. A solenoid valve will close off the connection to this vacuum pump once the user-set vacuum pressure is reached and the pump is turned off. To stay within the $100 budget for this project, we have been given a 2-Stage 50L/m Oil Free Lab Vacuum Pump on loan for this semester. The pump will connect to the chamber through standard PTFE tubing and push-fit connectors

If time allows and we are able to borrow a nitrogen tank, an additional solenoid and a PTFE Y-connector would allow the nitrogen tank to connect to the vacuum chamber through the same port as the vacuum pump.

## LCD Display and Rotary Encoder

The LCD display allows the user to interact with the temperature and pressure components of the brewing chamber. This display will be controlled using a rotary encoder with a push button. The menu style interface will allow you to control the vacuum level and brew time in the chamber, along with the nitrogenation pressure if time allows. The display will also monitor the temperature of the chamber and display it along with the time remaining and the current vacuum level.

# Criterion For Success

- A successful cold brew machine would be able to make cold brew coffee at or below room temperature in ten minutes at most.

- The machine must also allow the user to manually control the brew time and vacuum level as well as display the brew temperature.

- The machine must detect and report faults. If it is unable to reach the desired vacuum pressure or is inexplicably losing pressure, the machine must enter a safe ‘stop state’ and display a human readable error code.

- The reach goal for this project, not a criterion for success, would be the successful nitrogenation of the cold brew.

Project Videos